Optical component and methods of manufacturing

ABSTRACT

An optical component including microlenses and a transparent substrate oppositely arranged so that a plurality of projections formed on a bottom face of each microlens intersects with a plurality of projections formed on a surface of the transparent substrate, and each microlens and the transparent substrate are adhered to each other by the adhesive, and related methods of manufacturing.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §120 of U.S. patentapplication Ser. No. 12/662,716, entitled FIBER COLLIMATOR ARRAY filedApr. 29, 2010, now allowed, which also claims the benefit of U.S. patentapplication Ser. No. 12/314,677, entitled OPTICAL COMPONENT, FIBERCOLLIMATOR ARRAY AND WAVELENGTH SELECTIVE SWITCH filed Dec. 15, 2008,now U.S. Pat. No. 7,734,128, issued Jun. 8, 2010, which are herebyincorporated by reference in their entireties in this application. Thisapplication is based upon the claims of the benefit of priority of theprior Japanese Patent Application No. 2008-103773, filed on Apr. 11,2008, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are related to an optical componenthaving an adhesive structure in which a first optical member and asecond optical member are adhered to each other, a fiber collimatorarray and a wavelength selective switch including the fiber collimatorhaving the adhesive structure.

BACKGROUND

In recent years, with the speeding-up of optical signals in a trunksystem, it has been needed to process optical signals atultrahigh-speeds also in an optical switching function, such as, anoptical cross-connecting device or the like. Further, the switchingscale has also been significantly large due to an increase of wavelengthdivision multiplexing numbers in a wavelength division multiplexing(WDM) transmission technology.

Under such backgrounds, as one of relatively large scale opticalswitches, the development of a wavelength selective switch (WSS) hasbeen progressed. The wavelength selective switch is an optical devicecapable of selectively inputting or outputting arbitrary wavelengths,and a fiber collimator array is used as input/output ports thereof. Sucha fiber collimator array includes, for example: a fiber array in which aplurality of optical fibers is arrayed to correspond to the input andoutput ports; and a microlens array in which respective microlenses arearrayed on positions corresponding to the respective optical fibers.

Here, if an optical axis of each optical fiber and an optical axis ofeach microlens are deviated from each other, an insertion loss of thewavelength selective switch is increased. Therefore, there has beenknown a configuration in which each microlens is precisely aligned witheach optical fiber to thereby configure the fiber collimator array. In atechnology disclosed in Japanese Unexamined Patent Publication No.2007-328177, an optical fiber array block making up the fiber array anda silica microlens mounting base (to be simply referred to as a mountingbase, hereunder) making up the microlens array are integrated with eachother, and optimum positions on the mounting base are searched, so thatrespective microlenses are adhered to the optimum positions on themounting base.

However, since each microlens is significantly small, the adhesiveintensity thereof is low by being simply adhered to the mounting base,and therefore, there is a possibility that a resistance to vibration ora resistance to impact cannot be sufficiently ensured. Further, eachmicrolens may be required to be subjected to extremely minute positionadjustment, and therefore, it is also necessary to adopt a configurationin which such position adjustment can be easily performed, that is, aconfiguration in which each microlens is easily moved on the mountingbase.

The above described problems are common to optical components eachhaving an adhesive structure in which a relatively small optical member(first optical member) is adhered to another optical member (secondoptical member).

SUMMARY

The present invention provides a fiber collimator array as one aspectthereof. The fiber collimator array includes: a fiber array in which aplurality of optical fibers is arrayed; and a microlens array in whichmicrolenses are arrayed on a transparent substrate in positionscorresponding to the plurality of optical fibers, wherein each microlensand the transparent substrate are oppositely arranged so that aplurality of projections formed on a bottom face (adhesive surface) ofeach microlens intersects with a plurality of projections formed on asurface (adhesive surface) of the transparent substrate, and eachmicrolens and the transparent substrate are adhered to each other by anadhesive.

The present invention provides a wavelength selective switch as afurther aspect thereof. The wavelength selective switch has: (a) a fibercollimator array including: a fiber array in which a plurality ofoptical fibers containing an optical fiber corresponding to an inputport and optical fibers corresponding to output ports is arrayed; and amicrolens array in which microlenses are arrayed on a transparentsubstrate in positions corresponding to the plurality of optical fibers,and the fiber collimator array collimating a wavelength divisionmultiplexed optical signal input to the optical fiber corresponding tothe input port by the microlens corresponding to this optical fiber, tooutput the collimated wavelength division multiplexed optical signal;(b) a spectral element for spectrally separating the wavelength divisionmultiplexed optical signal output from the fiber collimator arrayaccording to wavelengths; (c) a condenser element for condensing theoptical signals of respective wavelengths spectrally separated by thespectral element on different positions; and (d) a mirror arrayincluding a plurality of mirrors arranged on the condensing positions ofthe optical signals of respective wavelengths, and the mirror arrayoutputting the optical signal reflected by each mirror from any one ofthe optical fibers corresponding to the output ports via the condenserelement, the spectral element and the fiber collimator array. Then, inthe fiber collimator array, each microlens and the transparent substrateare oppositely arranged so that a plurality of projections formed on abottom face of each microlens intersects with a plurality of projectionsformed on a surface of the transparent substrate, and each microlens andthe transparent substrate are adhered to each other by an adhesive.

The present invention provides an optical component as a furthermoreaspect thereof. The optical component has an adhesive structure in whicha first optical member and a second optical member are adhered to eachother, wherein the first optical member and the second optical memberare oppositely arranged so that a plurality of projections formed on thefirst optical member intersects with a plurality of projections formedon the second optical member, and the first optical member and thesecond optical member are adhered to each other by an adhesive.

The present invention provides a method of manufacturing a fibercollimator array as a still further aspect thereof. The fiber collimatorarray includes: a fiber array in which a plurality of optical fibers isarrayed; and a microlens array in which microlenses are arrayed on atransparent substrate in positions corresponding to the plurality ofoptical fibers. Then, the method of manufacturing the fiber collimatorarray includes: forming a plurality of projections on a bottom face ofeach microlens and on a surface of the transparent substrate; oppositelyarranging the bottom face of each microlens and the surface of thetransparent substrate so that the plurality of projections formed on thebottom face of each microlens intersects with the plurality ofprojections formed on the surface of the transparent substrate;adjusting a position of each microlens on the transparent substrate toarrange each microlens on an optical axis of each optical fiber; andadhering each microlens to the transparent substrate by an adhesive in astate where each microlens is arranged on the optical axis of eachoptical fiber.

The present invention provides a method of manufacturing an opticalcomponent having an adhesive structure in which a first optical memberand a second optical member are adhered to each other, as an even stillfurther aspect thereof. The method of manufacturing the opticalcomponent includes: forming a plurality of projections on the firstoptical member and on the second optical member; oppositely arrangingthe first optical member and the second optical member so that theplurality of projections formed on the first optical member intersectswith the plurality of projections formed on the second optical member;adjusting a position of the first optical member on the second opticalmember; and adhering the first optical member to the second opticalmember by an adhesive in a state where the position of the first opticalmember is adjusted on the second optical member.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims. It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an overview configuration of a fibercollimator array according to one embodiment of the present invention;

FIG. 2A and FIG. 2B are diagrams exemplarily illustrating methods ofimproving the adhesive intensity of microlens;

FIG. 3A to FIG. 3C are diagrams illustrating a first embodiment of anadhesive structure between each microlens and a transparent substrate inthe present embodiment;

FIG. 4 is a diagram illustrating a modified example of the firstembodiment;

FIG. 5 is a diagram illustrating a further modified example of the firstembodiment;

FIG. 6A and FIG. 6B are diagrams illustrating a second embodiment of theadhesive structure between each microlens and the transparent substratein the present embodiment;

FIG. 7 is a diagram illustrating a modified example of the secondembodiment;

FIG. 8 is a diagram illustrating a further modified example of thesecond embodiment;

FIG. 9A to FIG. 9D are diagrams typically illustrating arrangements(combinations) of a plurality of projections formed on each microlensand on the transparent substrate, in an adhesive portion;

FIG. 10 is a diagram illustrating the case where adhesive surfaces ofthe microlens and the transparent substrate are both inclined;

FIG. 11 is a diagram illustrating a configuration of a wavelengthselective switch to which the fiber collimator array according to thepresent embodiment is applied; and

FIG. 12 is a diagram for explaining a relation between an array pitch ofmicrolenses and a swing angle of a MEMS mirror in the wavelengthselective switch.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to drawings.

FIG. 1 illustrates an overview configuration of a fiber collimator arrayaccording to one embodiment of the present invention. As illustrated inFIG. 1, a fiber collimator array 1 includes: a fiber array 2 in which aplurality of optical fibers 21 (4 optical fibers in the figure) isarrayed; and a microlens array 3 in which a plurality of microlenses 31is arrayed. The fiber array 2 has a structure in which the plurality ofoptical fibers 21 is arrayed to be retained by a retainer block 22 at anend portion thereof. The microlens array 3 has a structure in which abottom face of each microlens 31 is adhered by the adhesive to aposition corresponding to each optical fiber 21 on a surface of a glassblock (transparent planar substrate, to be referred to as transparentsubstrate, hereunder) 32 formed of a glass material (silica) forexample. A rear face of the transparent substrate 32 (an opposite faceof the surface to which each microlens 31 is adhered) is integrated withthe retainer block 22 so as to be in tightly contact with end faces ofthe optical fibers 21. Each microlens 31 is subjected to precisepositioning (optical axis adjustment) to each optical fiber 21, andthereafter, is adhered to the transparent substrate 22. Namely, thetransparent substrate 22 is fixedly integrated with the retainer block32, and thereafter, an optimum position for each microlens 31 issearched while moving each microlens 31 on the transparent substrate 32,so that each microlens 31 is adhered to the transparent substrate 32 atthe optimum position. Incidentally, the optimum position means aposition at which an optical axis of each microlens 31 is coincidentwith an optical axis of the corresponding optical fiber 21.

Here, for fixing the transparent substrate 32 to the retainer block 22,since the end face of each optical fiber 21 may be in tightly contactwith the rear face of the transparent substrate 32, any method may beused. For example, the transparent substrate 32 may be fixed to theretainer block 22 by means of a fixing member (not illustrated in thefigure), or an adhesive portion may disposed on a region (notillustrated in the figure) of the retainer block 22 and the transparentsubstrate 32, to adhere the transparent substrate 32 and the retainerblock 22 in the adhesive portion.

Further, for adhering each microlens 31 to the transparent substrate 32,the adhesive having substantially same refractive index as eachmicrolens 31 (for example, the ultraviolet curing adhesive) is used.

Further, in adhering each microlens 31 to the transparent substrate 32,the adhesive may be previously applied on the bottom face (being anadhesive surface) of each microlens 31 or the surface (being an adhesivesurface) of the transparent substrate 32, to search the optimum positionof each microlens 31 on the transparent substrate 32, or the optimumposition of each microlens 31 may be searched on the transparentsubstrate 31 to supply the adhesive. In either of the cases, eachmicrolens 31 is adhered to the transparent substrate 32 (the adhesive iscured) in a state of being arranged on the optimum position.

In the case where the fiber collimator array 1 is configured as in theabove manner, as already described, the adhesive intensity of eachmicrolens 31 and the ease in position adjustment thereof need to beensured together.

As methods of improving the adhesive intensity, there are considered amethod of forming sections of the bottom face of each microlens 31 andof the surface of the transparent substrate 32 in serrated shapes toengage the serrated sections with each other as illustrated in FIG. 2A,a method of additionally disposing a reinforcing member to eachmicrolens 31 to increase an adhesive area to the transparent substrate32 as illustrated in FIG. 2B, and the like.

However, in the method of engaging the serrated sections with each other(FIG. 2A), although the adhesive area can be increased, it becomes hardto freely move each microlens 31 on the transparent substrate 32 forperforming the position adjustment or the like. On the other hand, inthe method of additionally disposing the reinforcing member (FIG. 2B),since a contact area (a frictional resistance) to the transparentsubstrate 32 is increased as well as the adhesive area, it becomes hardto finely adjust the position of each microlens 31 on the transparentsubstrate 32. Further, in the case where each microlens 31 is to bearrayed at a narrow pitch, the reinforcing member cannot be appliedsince each reinforcing member interferes with each other.

Therefore, in the present embodiment, a plurality of projections isformed on the bottom face (adhesive surface) of each microlens 31 and onthe surface (adhesive surface) of the transparent substrate 32, and thebottom face of each microlens 31 and the surface of the transparentsubstrate 32 are oppositely arranged so that the projections of eachmicrolens 31 intersect with the projections of the transparent substrate32, and each microlens and the transparent substrate are adhered to eachother by the adhesive.

Here, the height of top portion of the plurality of projections formedon the bottom face of each microlens 31 is all the same, and the heightof top portion of the plurality of projections formed on the surface ofthe transparent substrate 32 is all the same. Further, “projections”contains elongated portions protruding from adjacent regions or adjacentportions, and portions equivalent to respective serrations (teeth) forwhen the section is formed in a serrated shape or the like, as well as“ribs” formed on a plane or a configuration equivalent theretocorrespond to the elongated portions. Further, the elongated portioncontains a linear elongated portion, a curved elongated portion and acombination of the linear elongated portion and the curved elongatedportion.

Thus, when the plurality of projections formed on the bottom face ofeach microlens 31 and the plurality of projections formed on the surfaceof the transparent substrate 32 are arranged to intersect with eachother, to thereby be adhered to each other, each microlens 31 and thetransparent substrate 32 are in contact with each other directly or viaa small amount of the adhesive at the mutual top portions of theprojections. Namely, in the adhesive portion, the contact area betweeneach microlens 31 and the transparent substrate 32 is significantlyreduced, and at the same time, the adhesive area between each microlens31 and the transparent substrate 32 is increased. As a result, withoutthe necessity of extending an outer diameter of each microlens 31, theadhesive intensity of each microlens 31 is ensured, and in addition, theposition adjustment thereof can be performed easily.

In the present embodiment, the fiber collimator array 1 is specificallymanufactured as follows. Namely, the plurality of projections is formedon the bottom face of each microlens 31 and on the surface of thetransparent substrate 32, and the bottom face of each microlens 31 andthe surface of the transparent substrate 32 are oppositely arranged sothat the plurality of projections formed on the bottom face of eachmicrolens 31 intersect with the plurality of projections formed on thesurface of the transparent substrate 32. Subsequently, the positionadjustment of each microlens 31 is performed on the transparentsubstrate 32, to thereby arrange each microlens 31 on the optical axisof the corresponding optical fiber 21, and thereafter, each microlens 31and the transparent substrate 32 are adhered to each other by theadhesive.

Hereunder, there will be described specific examples of adhesivestructure between each microlens 31 and the transparent substrate 32.

FIG. 3A to FIG. 3C illustrate a first embodiment of the adhesivestructure between each microlens 31 and the transparent substrate 32.FIG. 3A illustrates each microlens 31, FIG. 3B illustrates thetransparent substrate 32, and FIG. 3C illustrates a state where eachmicrolens 31 is adhered to the transparent substrate 32. In thisembodiment, the sections of the bottom face (adhesive surface) of eachmicrolens 31 and of the surface (adhesive surface) of the transparentsubstrate 32 are formed in the serrated shapes (triangular wave shapes).

The serrated portions on the bottom face of each microlens 31 and on thesurface of the transparent substrate 32 can be formed by machining,anisotropic etching or the like. Here, the serrated portion on themicrolens 31 side and the serrated portion on the transparent substrate32 side need not to be formed in all the same shapes. Further, althoughtip ends of portions equivalent to the respective serrations (teeth) ofthe serrated portion are sharpened in the figure, these tip ends may beflattened or curved (formed in rounded shapes) by chamfering or thelike. In the first embodiment, the portions equivalent to the respectiveserrations (teeth) of the serrated portion (illustrated by X in thefigure) correspond to “projections”, and tip end portions of therespective serrations (illustrated by Y in the figure) correspond to“top portions of the projections”.

In the first embodiment, as illustrated in FIG. 3A and FIG. 3B, thesections of the bottom face of each microlens 31 and of the surface ofthe transparent substrate 32 are formed in the serrated shapes, to beoppositely arranged so that the serrated portion formed on the bottomface of each microlens 31 are not engaged with the serrated portionformed on the surface of the transparent substrate 32, that is, so thatthe serrated portion of each microlens 31 intersect with the serratedportion of the transparent substrate 32. Preferably, as illustrated inFIG. 3C, the bottom face of each microlens 31 and the surface of thetransparent substrate 32 are oppositely arranged so that the serratedportions thereof are approximately orthogonal to each other.

Then, the position adjustment of each microlens 31 is performed on thetransparent substrate 32, and thereafter, each microlens 31 is adheredto the transparent substrate 32 by the adhesive. At this time, asalready described, before performing the position adjustment, theadhesive may be previously applied on the bottom face of each microlens31 and/or on the surface of the transparent substrate 32, to be cured ata time point when the position adjustment is finished, or afterperforming the position adjustment, the adhesive may be supplied betweeneach microlens 31 and the transparent substrate 32 to be cured.

As a result, the bottom face of each microlens 31 and the surface of thetransparent substrate 32 are in intermittently contact with each otherdirectly or via the small amount of the adhesive at the tip end portions(Y) of the serrations (teeth) of the respective serrated portionsthereof, that is, at the top portions of the projections (X). Here,especially in the case where the tip ends of the respective serrations(teeth) are sharpened or curved (rounded shapes), each microlens 31 andthe transparent substrate 32 are in point contact with each other at aplurality of points, whereas in the case where the tip ends of therespective serrations (teeth) are flattened, each microlens 31 and thetransparent substrate 32 are in face-to-face contact with each other byrelatively small areas at a plurality of sites. In either cases, thecontact area between each microlens 31 and the transparent substrate 32is significantly reduced, and at the same time, the adhesive areabetween each microlens 31 and the transparent substrate 32 is increased,compared with the case where the bottom face of each microlens 31 andthe surface of the transparent substrate 32 are formed in the sameplane. As a result, the adhesive intensity of each microlens 31 can beensured while easily performing the position adjustment (for example,optical axis adjustment) thereof on the transparent substrate 32.

FIG. 4 and FIG. 5 illustrate modified examples of the first embodiment.Briefly describing, in FIG. 4, the sections of the bottom face of eachmicrolens 31 and of the surface of the transparent substrate 32 areformed in sinusoidal wave shapes, and in FIG. 5, the sections thereofare formed in continuous semicircular (circular arc) shapes. Theseshapes can be formed by machining, anisotropy etching or the like. Then,similarly to the first embodiment, each microlens 31 and the transparentsubstrate 32 are oppositely arranged so that the projections of eachmicrolens 31 and the projections of the transparent substrate 32intersect with each other (preferably, are approximately orthogonal toeach other), to thereby be adhered to each other by the adhesive. Alsoin these cases, the section on the microlens 31 side and the section onthe transparent substrate 32 need not to be formed in all the sameshapes.

FIG. 6 illustrates a second embodiment of the adhesive structure betweeneach microlens 31 and the transparent substrate 32. FIG. 6A illustrateseach microlens 31 and FIG. 6B illustrates the transparent substrate 32.In the second embodiment, a plurality of ribs each having a triangularcross section is formed at a constant pitch on the bottom face (adhesivesurface) of each microlens 31 and on the surface (adhesive surface) ofthe transparent substrate 32. These ribs can also be formed bymachining, anisotropic etching or the like. Further, top portions of theribs may be formed in curved faces (rounded faces) by chamfering or thelike, and the ribs of each microlens 31 and the ribs of the transparentsubstrate 32 need not to be formed in all the same shapes.

Then, each microlens 31 and the transparent substrate 32 are oppositelyarranged so that ribs 35 formed on the bottom face of each microlens 31and ribs 36 formed on the surface of the transparent substrate 32intersect with each other (preferably, are approximately orthogonal toeach other), to be adhered to each other by the adhesive. Thus, eachmicrolens 31 and the transparent substrate are in point contact witheach other at top portions of the ribs 35 and of the ribs 36, so thatthe contact area between each microlens 31 and the transparent substrate32 is significantly reduced, and at the same time, the adhesive areabetween each microlens 31 and the transparent substrate 32 is increased.As a result, similarly to the first embodiment, the adhesive intensityof each microlens 31 can be ensured, and at the same time, the positionadjustment thereof can be easily ensured.

Incidentally, as a modified example of the second embodiment, in placeof the ribs 35 and the ribs 36 each having the triangular cross section,there may used ribs each having a trapezoidal cross section asillustrated in FIG. 7 or ribs each having a semi-circular cross sectionas illustrated in FIG. 8. In the case such ribs are used, effectssimilar to those in the second embodiment can be obtained.

Each microlens 31 and the transparent substrate 32 may be oppositelyarranged so that the projections formed on the bottom face of eachmicrolens 31 and the projections formed on the surface of thetransparent substrate 32 intersect with each other, to be adhered toeach other, and accordingly, the adhesive structure between eachmicrolens 31 and the transparent substrate 32 is not limited to thefirst embodiment, the second embodiment or the modified examples of theembodiments. Namely, there may be made various arrangements(combinations) of the plurality of projections formed on the bottom faceof each microlens 31 and the plurality of projections formed on thesurface of the transparent substrate 32 in the adhesive portion. Some ofthe various arrangements (combinations) will be exemplarily shown in thefollowings.

FIG. 9A to FIG. 9D typically illustrate the arrangements (combinations)of the plurality of projections formed on the bottom face of eachmicrolens 31 and the plurality of projections formed on the surface ofthe transparent substrate 32 in the adhesive portion between eachmicrolens 31 and the transparent substrate 32. In FIG. 9, lines orcircles appearing on the bottom face of each microlens and on thesurface of the transparent substrate indicate the top portions of therespective projections (tip ends of the ribs or serrated edge portionsof the serrated sections), and FIG. 9A corresponds to the firstembodiment (FIG. 3).

FIG. 9B illustrates a combination example for when the plurality ofobliquely and linearly extending projections is formed at a constantpitch on the surface of the transparent substrate 32.

FIG. 9C illustrates a combination example for when the plurality ofprojections extending in radial from a predetermined position (startingpoint) of a circumferential portion is formed on the bottom face of eachmicrolens 31 and on the surface of the transparent substrate 32. In thiscase, even after the position of each microlens 31 is adjusted, bysupplying the adhesive from the starting point on the microlens 31 sideor/and from the starting point on the transparent substrate 32 side, theadhesive can be efficiently spread between the bottom face of eachmicrolens 31 and the surface of the transparent substrate 32.

FIG. 9D illustrates a combination example for when the plurality ofprojections in concentric circles is formed on the bottom face of eachmicrolens 31 whereas the plurality of linear projections is formed at aconstant pitch on the surface of the transparent substrate 32. In thiscase, the adhesive retention capacity on the bottom face of eachmicrolens 31 can be improved.

By using the above described adhesive structure between each microlens31 and the transparent substrate 32, it is possible to easily performthe position adjustment of each microlens 31 on the transparentsubstrate 32, and also, it is possible to ensure the adhesive intensitythereof without the necessity of extending the outer diameter of eachmicrolens 31 to thereby improve a resistance to vibration of the fibercollimator array and a resistance to impact thereof. Incidentally, asillustrated in FIG. 10, even in the case where the adhesive surfaces ofeach microlens 31 and of the transparent substrate 32 are inclined, thepresent invention can surely be applied.

According to such a fiber collimator array and such a method ofmanufacturing the fiber collimator array, it is possible to easilyperform the position adjustment (for example, the optical axisadjustment to the optical fiber) of each microlens, and also, it ispossible to ensure the adhesive intensity thereof without the necessityof extending the outer diameter of each microlens to thereby improve theresistance to vibration and the resistance to impact.

Next, there will be described the application of the fiber collimatorarray having the above described adhesive structure between eachmicrolens and the transparent substrate to a wavelength selective switch(WSS).

FIG. 11 illustrates one example of wavelength selective switch. Asillustrated in FIG. 11, a wavelength selective switch 100 has: a fibercollimator array 110; a spectral element 120; a condenser element 130;and a mirror array 140.

The fiber collimator array 110 includes a fiber array 110A in which aplurality of optical fibers is arrayed and a microlens array 110B inwhich a plurality of microlenses is arrayed. The fiber array 110A has astructure in which an optical fiber (a single optical fiber in the FIG.111 _(IN) corresponding to an input port and optical fibers 111_(OUT)(#1) to 111 _(OUT)(#N) (five optical fibers in the figure)corresponding to output ports are arrayed in one direction, to beretained by a retainer block 112 at end portions thereof. The microlensarray 110B has a structure in which respective microlenses 113 areadhered to positions corresponding to the respective optical fibers 111on a transparent substrate 114. In the fiber collimator array 110, awavelength division multiplexed optical signal input from the input port(the optical fiber 111 _(IN)) travels through the transparent substrate114 while being spread, and is collimated by the corresponding microlens113 to be converted into a parallel light to thereby be output.

The spectral element 120 is a diffraction grating for example, and(spectrally) separates the wavelength division multiplexed opticalsignal output from the fiber collimator array 110 to different angledirections for respective wavelengths.

The condenser element 130 is a condenser lens for example, and condensesoptical signals of respective wavelengths (respective wavelengthchannels) (spectrally) separated by the spectral element 120 ondifferent positions.

The mirror array 140 includes a plurality of mirrors (#1 to #N) disposedon condensing positions of the optical signals of respectivewavelengths. Each mirror is a MEMS mirror manufactured using a MEMS(Micro Electro Mechanical Systems) technology. The respective opticalsignals (respective wavelength channels) reached the mirror array 140are reflected by the corresponding MEMS mirrors to be turned topredetermined directions. Here, each MEMS mirror is supported by a pairof torsion bars for example, to be swung around the torsion bars, and iscontrolled by a control section (not shown in the figure) at an angle(swinging position) corresponding to a position of the output port setas the output determination of each optical signal. Thus, the opticalsignal (wavelength channel) reflected by each MEMS mirror of the mirrorarray 140 passes through the condenser element 130, the spectral element120 and the fiber collimator array 110 in this order, to be output fromthe desired output port.

In the wavelength selective switch of such a configuration, the fibercollimator array 110 is required to ensure the adhesive intensity ofeach microlens 113 to the transparent substrate 114, and to ensure theease in position adjustment of each microlens 113 on the transparentsubstrate 114. Further, as illustrated in FIG. 12, the array pitch ofeach microlens 113 and a swing angle of each MEMS mirror are in anapproximately proportional relation. Therefore, due to the restrictionof the swing angle of each MEMS mirror or the like, the array pitch ofeach microlens 113 cannot be so extended, and therefore, it is hard toensure the adhesive intensity by a reinforcing member (refer to FIG.2B).

In this point, each adhesive structure between each microlens and thetransparent substrate as described in FIG. 1 to FIG. 9 ensures theadhesive intensity of each microlens to the transparent substratewithout the necessity of extending the outer diameter of each microlens,and in addition, ensures the ease in position adjustment of eachmicrolens on the transparent substrate, and accordingly, is suitable forthe wavelength selective switch described above.

Therefore, in the fiber collimator array 110 of the wavelength selectiveswitch 100 according to the present embodiment, each adhesive structurebetween each microlens and the transparent substrate as described inFIG. 1 to FIG. 9 is adopted.

According to the wavelength selective switch 100 in the presentembodiment, it is possible to easily perform the optical axis adjustmentbetween each optical fiber 112 and each microlens 113, and also, toensure the adhesive intensity of each microlens 113. Thus, an increasein insertion loss of the wavelength selective switch 100 is suppressed,and the resistance to vibration and the resistance to impact areimproved in the entire wavelength selective switch 100.

In the above descriptions, there has been described the fiber collimatorarray and the wavelength selective switch comprising the fibercollimator array. However, as already described, the present inventioncan be applied to an optical component configured such that a relativelysmall member (element) is adhered to another member (element) whilebeing subjected to the position adjustment. In such a case, it may beconsidered that each microlens is a first optical member, thetransparent substrate is a second optical member, and the fibercollimator array or the microlens array is an optical component havingan adhesive structure in which the first optical member and the secondoptical member are adhered to each other.

According to such an optical component, it is possible to easily performthe position adjustment of the first optical member on the secondoptical member, and also, to improve the adhesive intensity between thefirst optical member and the second optical member.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the principlesof the invention and the concepts contributed by the inventor forfurthering the art, and are to be construed as being without limitationto such specifically recited examples and conditions, nor does theorganization of such examples in the specification relate to a showingof the superiority and inferiority of the invention. Although theembodiments of the present invention have been described in detail, itshould be understood that the various changes, substitutions, andalterations could be made hereto without departing from the spirit andscope of the invention.

1. An optical component having an adhesive structure in which a firstoptical member and a second optical member are adhered to each other,wherein the first optical member and the second optical member areoppositely arranged so that a plurality of projections formed on thefirst optical member intersects with a plurality of projections formedon the second optical member, and the first optical member and thesecond optical member are adhered to each other by an adhesive.
 2. Anoptical component according to claim 1, wherein, in an adhesive portion,the first optical member and the second optical member are inintermittently contact with each other directly or via the adhesive attop portions of the plurality of projections formed on the first opticalmember and top portions of the plurality of projections formed on thesecond optical member.
 3. An optical component according to claim 2,wherein the top portions of the plurality of projections formed on thefirst optical member and the top portions of the plurality ofprojections formed on the second optical member are in point contactwith each other.
 4. An optical component according to claim 1, whereinthe first optical member and the second optical member each has aserrated portion of which section is formed in a serrated shape, and thefirst optical member and the second optical member are oppositelyarranged so that the serrated portion of the first optical member andthe serrated portion of the second optical member are not engaged witheach other, and the first optical member and the second optical memberare adhered to each other by the adhesive.
 5. An optical componentaccording to claim 1, wherein the first optical member is subjected toposition adjustment on the second optical member before being adhered tothe second optical member.
 6. A method of manufacturing a fibercollimator array including a fiber array in which a plurality of opticalfibers is arrayed and a microlens array in which microlenses are arrayedon a transparent substrate in positions corresponding to the pluralityof optical fibers, the method comprising: forming a plurality ofprojections on a bottom face of each microlens and on a surface of thetransparent substrate; oppositely arranging the bottom face of eachmicrolens and the surface of the transparent substrate so that theplurality of projections formed on the bottom face of each microlensintersects with the plurality of projections formed on the surface ofthe transparent substrate; and adjusting a position of each microlens onthe transparent substrate to arrange each microlens on an optical axisof each optical fiber, to adhere each microlens to the transparentsubstrate by an adhesive.
 7. A method of manufacturing an opticalcomponent having an adhesive structure in which a first optical memberand a second optical member are adhered to each other, the methodcomprising: forming a plurality of projections on the first opticalmember and on the second optical member; oppositely arranging the firstoptical member and the second optical member so that the plurality ofprojections formed on the first optical member intersects with theplurality of projections formed on the second optical member; andadjusting a position of the first optical member on the second opticalmember to adhere the first optical member to the second optical memberby an adhesive.